1. Field of the Invention
This invention relates to patient support means for use with beds of the type in which the patient is supported on a flexible web of mesh or net form. A bed of this type is hereinafter referred to generally as a "net bed", and the web thereof as "the net".
2. Description of the Prior Art
The net may be slung between two shafts on to which the ends of the net are respectively wound, and such net beds which are in general use are disclosed in U.S. Pat. No. 4,270,234 provide major advantages in the handling of patients. The net-supporting shafts of the bed can be turned in the same direction to transfer the net from one shaft to the other, whereby the patient on the net is turned and repositioned thereon, or the shafts can be turned in opposite directions to raise or lower the patient with respect to a conventional mattress or other support surface below the net. Net beds in general are also particularly valuable in the prevention and treatment of bed sores as the net conforms to the shape of the patient who is thus supported with a substantially uniform pressure thereby eliminating high pressure loading of specific areas of the body and the mesh provides excellent ventilation of the skin.
It will be appreciated from the foregoing that the material and construction of the net, and the mesh size thereof, must be such as to allow the net to conform to the shape of the patient, thereby spreading the load and avoiding localized high pressure areas, and also to allow adequate ventilation. However, the mesh apertures are desirably small enough to avoid the fingers of a patient being trapped therein.
The nets at present in use, designed to satisfy these requirements, suffer from a number of disadvantages. A first disadvantage is that conforming of the net to the body shape of a patient results in excessive shortening of the net between the shafts, when such are employed, with the result that the effective length of the net available to support the patient is considerably reduced. Another disadvantage is that the nets tend to creep along the supporting shafts which, although in general more-or-less parallel, are often slightly inclined so as to have a narrower spacing at the foot end to facilitate simultaneous turning at that end by the two hands of a nurse. This shaft inclination increases the creepage problem. A further disadvantage with net beds generally is that after use the nets tend to retain the sag produced when supporting the patient and thus they do not readily, if at all, return to the original unstretched condition.